• 대한영양사협회학술지
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• 제24권2호
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• pp.141-158
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• 2018

The purpose of this study is to observe students' eating habits and to evaluate the necessity of high school breakfast service by surveying concerned persons such as high school dietitians, parents, and students to find practical solutions to decrease the breakfast-skipping rate of the high school students in Chungcheong. The data were collected from 75 dietitians, 584 students, and 420 parents. Parents and students participated the survey more positively, and the more monthly income participants' families had, the probability of participation increased by 1.5 times (OR=1.452). Parents suggested that breakfast should be offered at a lower price (1,000~2,000 won) than school lunch, and for the school breakfast cost, they preferred to bear the expense together with schools. For the type of breakfast, the dietitians preferred convenient foodservice (40.0%), the students preferred simple meals such as bread, milk, fruit and salad (3.97), and Kimbap, Joomukbap et al (3.93) rather than Korean traditional foods (3.76) such as rice, soup and side dish. The dietitians answered 'needed' and 'very much needed' to the necessity of breakfast relatively low by 30.7%. As the result of the study, the researchers suggest the execution of school breakfast program should start first for the students who cannot have breakfast at home. Moreover, more studies should be conducted to reduce the constantly increasing rate of breakfast-skipping rate of high school students.

• Structural Engineering and Mechanics
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• 제75권6호
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• pp.747-769
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• 2020

This paper provides a semi-analytical approach to investigate the variations of 3D displacement components, electric potential, stresses, electric displacements and transverse vibration frequencies in laminated piezoelectric composite plates based on the scaled boundary finite element method (SBFEM) and the precise integration algorithm (PIA). The proposed approach can analyze the static and dynamic responses of multilayered piezoelectric plates with any number of laminae, various geometrical shapes, boundary conditions, thickness-to-length ratios and stacking sequences. Only a longitudinal surface of the plate is discretized into 2D elements, which helps to improve the computational efficiency. Comparing with plate theories and other numerical methods, only three displacement components and the electric potential are set as the basic unknown variables and can be represented analytically through the transverse direction. The whole derivation is built upon the three dimensional key equations of elasticity for the piezoelectric materials and no assumptions on the plate kinematics have been taken. By virtue of the equilibrium equations, the constitutive relations and the introduced set of scaled boundary coordinates, three-dimensional governing partial differential equations are converted into the second order ordinary differential matrix equation. Furthermore, aided by the introduced internal nodal force, a first order ordinary differential equation is obtained with its general solution in the form of a matrix exponent. To further improve the accuracy of the matrix exponent in the SBFEM, the PIA is employed to make sure any desired accuracy of the mechanical and electric variables. By virtue of the kinetic energy technique, the global mass matrix of the composite plates constituted by piezoelectric laminae is constructed for the first time based on the SBFEM. Finally, comparisons with the exact solutions and available results are made to confirm the accuracy and effectiveness of the developed methodology. What's more, the effect of boundary conditions, thickness-to-length ratios and stacking sequences of laminae on the distributions of natural frequencies, mechanical and electric fields in laminated piezoelectric composite plates is evaluated.

• Membrane and Water Treatment
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• 제11권5호
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• pp.323-331
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• 2020

With the increasing demand on reverse osmosis (RO) membranes for water purification worldwide, the number of disposed membrane elements is expected to increase accordingly. Thus, recycling and reuse of end-of-life RO membranes should be a global environmental action. In this work, we aim to reuse the spent RO membrane for nanofiltration (NF) and ultrafiltration (UF) process by subjecting the spent membrane to solvent and oxidizing solution treatment, respectively. Our results showed that solvent-treated RO membrane could perform as good as commercial NF membrane by achieving similar separation efficiencies, but with reduced water permeability due to membrane surface fouling. By degrading the polyamide layer of RO membrane, the transformed membrane could achieve high water permeability (85.6 L/㎡.h.bar) and excellent rejection against macromolecules (at least 87.4%), suggesting its reuse potential as UF membrane. More importantly, our findings showed that in-situ transformation on the spent RO membrane using solvent and oxidizing solution could be safely conducted as the properties of the entire spiral wound element did not show significant changes upon prolonged exposure of these two solutions. Our findings are important to open up new possibilities for the discarded RO membranes for reuse in NF and UF process, prolonging the lifespan of spent membranes and promoting the sustainability of the membrane process.

• 산업경영시스템학회지
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• 제33권1호
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• pp.17-23
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• 2010

The corporate R&D(Research and Development) has a primary role of new product development and its potential is the most crucial factor to estimate corporate future value. However, its systemic inadequacies and inefficiencies, the shorten product life-cycle to satisfy customer needs, the global operations by outsourcing strategy, and the reduction of product cost, are starting to expose to R&D business processes. The three-phased execution strategy for R&D innovation is introduced to establish master plan for new R&D model. From information technology point of view, PLM(Product Life-cycle Management) is one of the business total solutions in product development area. It is not a system, but the strategic business approach that collaboratively manage the product from beginning stage to end of life in all business areas PLM functions and capabilities are usually used as references to re-design new R&D process. BPA(Business Process Assessment) and 5DP(Design Parameters) in PI6sigma developed by Samsung SDS Consulting division are introduced to establish R&D master plan and re-design process respectively. This research provides a case study for R&D process innovation. How process assessment and PMM(Process Maturity Model) can be applied in business processes, and also it explains process re-design by 5DP method.

• 통상정보연구
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• 제9권3호
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• pp.181-204
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• 2007

Trade Portal Site(TPS) is one of the innovative skills which makes it possible for small and medium-sized enterprises(SMEs) to manage international trade activities more efficiently by using the newest information and telecommunication technology. Based on performance and an existing research related to using information technology, this research analyzed the user's degree of utilization of TPSs which moderates effects between SMEs characteristics and export performance of SMEs. According to the results of the empirical study on actual data of 194 sample firms by using moderated regression analysis, there are significant only organizational characteristics among determinants(such as organizational characteristics, export characteristics) as the degree of utilization of TPSs. These research results provide many useful insights to the CEOs of SMEs using the services of TPSs, e-Trade system developers, and government policy makers. First, CEOs and managers of SMEs should have thorough understanding of the importance of the new information technology and e-Trade and positively adopt new e-Trade solutions and systems to their export processes to enhance global competitiveness. Second, TPS managers and e-Trade systems developers must concentrate on improving the user's degree of utilization of TPSs. Finally, the government agency should develop the various e-Trade promotion policies to support the efforts of SMEs organizational characteristics and TPS to increase the degree of utilization of TPS, which have positive effects on the export performance of SMEs.

• 한국측량학회지
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• 제27권6호
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• pp.723-731
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• 2009

최근 지구 온난화 등의 영향으로 집중호우의 빈도가 급증하고 있으며, 강우강도 역시 강해지고 있는 실정이다. 이에 따라 국지적인 홍수피해가 증가하고 있으며, 댐 상류지역에서는 지형적 특성과 댐에 의한 배수위의 영향으로 많은 피해가 발생하고 있다. 그러나 대부분의 홍수피해의 경감대책은 인구밀집지역인 하류지역에 집중되고 있어 상류지역의 침수는 상대적으로 소홀히 다뤄지고 있다. 이에 본 연구에서는 정밀 3차원 지형모델을 구축하여 상류지역의 지형적 특성을 반영하고 강우발생시 유출특성을 조사하여 홍수시뮬레이션을 수행함으로써 상류지역의 침수피해양상과 침수취약지역을 분석하고자 하였다. 연구 결과, 홍수시뮬레이션에 의해 상류지역의 침수발생을 재현할 수 있었으며, 발생 가능한 강우에 대한 가상 홍수 시나리오에 의해 시뮬레이션을 수행함으로써 침수 취약지역과 그 피해면적을 효과적으로 도출할 수 있었다. 또한 침수 취약 지역에 대한 침수 예측도를 제작함으로써 강우 규모별 피해지역의 신속한 판단과 침수방어 대책의 수립에 효과적으로 활용할 수 있을 것으로 사료된다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.699-703
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• 2007

최근 국내 건설업체들의 해외 플랜트 수주는 2003년 이후 지속적인 성장세를 보이고 있다. 2006년에는 254억 달러를 기록하였고, 산업자원부에서 발표한 2007년 1/4분기까지의 집계가 벌써 90억 달러에 육박하고 있다. 향후 세계시장에서의 플랜트 산업은 지속적인 성장을 할 것으로 전망하고 있다. 그러나 이러한 해외 플랜트 수주에 있어 국내 대형건설업체들을 비롯한 중소건설업체들이 중동지역을 중심으로 세계 곳곳으로 뻗어나가는 현 시점에서 플랜트 전문인력 부족이라는 난관에 부딪혀있다. 플랜트 건설산업의 발전속도는 빠르게 증가하고 있으나, 이에 반해 전문기술인력의 충원이 잘 이루어지지 않고, 충원되는 신규인력의 경우에도 세부화된 전공 이수자이기에 그에 따른 새로운 교육이 필요하고 빠른 현장 투입이 불가능한 실정이다. 또한 사업관리, 파이낸싱 분야의 인력도 크게 부족하다. 따라서 본 연구에서는 플랜트 산업의 경쟁력 강화를 위하여 전문 인력양성을 위한 효율적인 방안에 대해 알아보고, 현실적인 대안을 제시하고자 한다.

• 정보보호학회논문지
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• 제27권3호
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• pp.591-605
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• 2017

개인정보자기결정권이란 "자신에 관한 정보가 언제 누구에게 어느 범위까지 알려지고 또 이용되도록 할 것인지를 그 정보주체가 스스로 결정할 수 있는 권리"로서 2005년 헌법재판소에서 헌법상으로 인정한 권리이다. 개인정보 자기결정권 증에는 정보주체가 정보보유자가 보유중인 본인의 정보에 대한 현황 및 처리내역을 열람할 수 있도록 하는 자기정보접근권이 있다. 이러한 자기정보접근권을 보장하기 위하여 개인정보와 관련된 각종 법률에서 정보보유자에게 개인정보의 처리에 관한 사항을 정보주체에게 무조건적으로 통지하도록 의무(이하 "무조건적 자기정보접근권")를 부여하고 있다. 본 논문에서는 이러한 무조건적 자기정보접근권 부여에 대한 국내 법률 현황 및 외국의 규제 현황을 분석한다. 이어서 국내 기업들의 대응 사례를 소개하고, 관련 문제점 및 개선방안을 제시하며 결론을 낼 것이다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.255-260
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• 2006

Safety-critical navigation systems have to provide 'reliable' position solutions, i.e., they must detect and exclude measurement or system faults and estimate the uncertainty of the solution. To obtain more accurate and reliable navigation systems, various filtering methods have been employed to reduce measurement noise level, or integrate sensors, such as global navigation satellite system/inertial navigation system (GNSS/INS) integration. Recently, particle filters have attracted attention, because they can deal with nonlinear/non-Gaussian systems. In most GNSS applications, the GNSS measurement noise is assumed to follow a Gaussian distribution, but this is not true. Therefore, we have proposed a fault detection and exclusion method using particle filters assuming non-Gaussian measurement noise. The performance of our method was contrasted with that of conventional Kalman filter methods with an assumed Gaussian noise. Since the Kalman filters presume that measurement noise follows a Gaussian distribution, they used an overbounded standard deviation to represent the measurement noise distribution, and since the overbound standard deviations were too conservative compared to the actual distributions, this degraded the integrity-monitoring performance of the filters. A simulation was performed to show the improvement in performance of our proposed particle filter method by not using the sigma overbounding. The results show that our method could detect smaller measurement biases and reduced the protection level by 30% versus the Kalman filter method based on an overbound sigma, which motivates us to use an actual noise model instead of the overbounding or improve the overbounding methods.

• KIEE International Transactions on Power Engineering
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• 제5A권3호
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• pp.269-279
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• 2005

This paper presents an application of the parallel Adaptive Evolutionary Algorithm (AEA) to search an optimal solution of a reconfiguration in distribution systems. The aim of the reconfiguration is to determine the appropriate switch position to be opened for loss minimization in radial distribution systems, which is a discrete optimization problem. This problem has many constraints and it is very difficult to find the optimal switch position because of its numerous local minima. In this investigation, a parallel AEA was developed for the reconfiguration of the distribution system. In parallel AEA, a genetic algorithm (GA) and an evolution strategy (ES) in an adaptive manner are used in order to combine the merits of two different evolutionary algorithms: the global search capability of GA and the local search capability of ES. In the reproduction procedure, proportions of the population by GA and ES are adaptively modulated according to the fitness. After AEA operations, the best solutions of AEA processors are transferred to the neighboring processors. For parallel computing, a PC-cluster system consisting of 8 PCs·was developed. Each PC employs the 2 GHz Pentium IV CPU, and is connected with others through switch based fast Ethernet. The new developed algorithm has been tested and is compared to distribution systems in the reference paper to verify the usefulness of the proposed method. From the simulation results, it is found that the proposed algorithm is efficient and robust for distribution system reconfiguration in terms of the solution quality, speedup, efficiency, and computation time.